Improvement in the process of manufacturing white lead



e. CARY.

Making White Lead.

N0. 3 f Patented Sept. 24, 1861.

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miuoTo-umamnx (mannavnbczsaa PATENT OFFICE.

GEORGE CARY, OF CLEVELAND, Ol'IIO.

IMPROVEMENT IN THE PROCESS OF MANUFACTURING WHITE LEAD.

' Specification forming part of Letters Patent No. 33,337, dated September 24, 1861..

To aZZ whom it may concern:

, Be it known that I, GEORGE CARY, of Gleveland, in the county of C-uyahoga and State of Ohio, have invented new and useful Improvements in the Process of Manufacturing lVhite Lead; and I do hereby declare that the following is a full and complete description of the construction of the apparatus used and of the ingredients and manipulations therein concerned.

My improvement consists in subjecting metallic lead to the action of vapors arising from heated vinegar oflow proof, which gives at once sufficient aqueous vapor to corrode and acetic-acid vapor to form the subacetate of lead, and thus prepare it to receive the car bonic-acid gas which forms the carbonate of the protoxide or white lead. The abovenamed agents are introduced into suitable chambers or rooms fitted up for that purpose and charged with metallic lead, the said agents being introduced simultaneously and continuously, as hereinafter specified. The rooms are made as tight as practicable with matched boards, but are not absolutely air-tight, and are not opened at any time during the entire process for the purpose of introducing or allowing the circulation of atmospheric air, or for the introduction of any other material than those mentioned above, or for allowing any of the agents employed to escape. By these means I not only greatly accelerate the process of corroding and carbonizing the lead, but do it in a manner more effectually and economically and in a manner less prejudicial to the health of the workmen than by any other process withwvhich I am acquainted.

In the accompanying drawings, Figure 1 is a top view of the apparatus with the cover of the chamber removed for the purpose of showing the interior. Fig. 2 is a front elevation. Fig. 3 is a side elevation. Fig. l is a view of the pipes for the distribution of the aqueous and acetic-acid vapors; and Fig. 5 is a vertical section of the chamber, showing also a cross-section of the main distributing-pipe in Fig. 4.

A in the several figures represents a chamber about eight or ten feet square and about seven or eight feet high with a door upon one side opening outward. In Fig. 1 it is represented as having the top removed for the purpose of showing the interior. This chamber may be made of good matched boards and as tight as practicable without luting the joints; but it is not necessary that it should be absolutely air-tight.

In the top view shown in Fig. -1, I) Z) represent the upper range of slats, upon which the coils of lead are placed. These slats are placed about an inch apart. There are several of such ranges forsupporting the coils of lead during the process, and they are placed about eighteen inches apart, as shown in Fig. 5, the lowest range being a little above the pipe for the admission of the vapors of water and acetic acid from the boiler K.

E represents the pipe for the admission of carbonic-acid gas, and enters the room near the top. This pipe is furnished with two stop-cocks ff, by means of which the gas can be admitted into the room or shut 01f, as de- I sired.

B, Fig. 4, represents the distribution-pipes for the aqueous and acetic-acid vapor after they enter the chamber, and shows the manner in which these vapors are admitted into the room at the bottom thereof, as seen in Fig. 5.

The pipe F, leading from the boiler K, enters the room near the bottom, as above stated, and continues to the opposite side, two series ofpipes branching off on either side parallel with the bottom of the room and extending nearly to the sides thereof. These branches or pipes are provided with a number of small holes on each side and on the top for the purpose of distributing through the room the vapors admitted by the pipe F. The pipe F is furnished with a stop-cock g for the purpose of controlling the admission of vapor.

0 represents a reservoir for the carbonicacid gas, and is connected with the furnace D by the pipe G. The furnace D, in which the carbonic acid is generated by means of the combustion of charcoal, is furnished with two pipes G and II. The pipe G leads to the reservoir 0, and is provided with a stopcock f for the purpose of turning all the products of combustion through the pipe H at pleasure, in order to allow the escape of smoke arising from the combustion of any uncharred wood when the furnace D is freshly charged. By closing the stop-cock h and opening the stop-cocks f the carbonic acid will pass up into the reservoir C and into the chamber A. It will be observed by reference to Fig. 3 that the pipe H opens into the open air for the purpose above stated.

K represents aboiler in which the vapor of water and acetic-acid vapor are generated. This rests upon the furnace L and communicates with the chamber or room A by means of the pipe F, as before stated, for the purpose of conveying and distributing the vapors thus formed, as set forth.

Figs. 2 and 3 represent the outside of a chamber in which the lead is placed, showing the arrangement of the pipe E for the admission of carbonic acid, and of the pipe F for the admission of the vapors of acetic acid and Water from the boilerK. Thedoor N is furnished with a piece of plate-glass 0, through which the operator may watch the progress of the process. In order to keep up the requisite heat in the chamber A, a steampipe may be introduced" from the boiler K and coiled around the chamber on the inside and the condensed vapor conveyed again into the boiler.

Having thus fully described the apparatus necessary for carrying my improvement into effect, I will now describe the process; I

In the first place the metallic lead rolled into'suitable coils is placed upon each-series of the slats b 1), Figs. 1' and 3, until the chamber is filled. not again opened for any purpose until the operation is completed. Vinegar, of about 1 one-third the commercial strength is then placed in the boiler K, and by means of heat in the furnace L the vapors of acetic acid" and Water are evolved therefrom and carried conjointly and gradually into the chamber A by means of the pipe E and distributed by The room is then closed, and

the system of pipes 13 a (1,, (seen in Figs. 4 and 5,) and equally diffused th-rou-glioutth'echamber, first corroding the metallic lead, the protoxide thus formed being instantly converted into the subacetate by virtue of the presence of acetic-acid vapor. Oonjointly and simultaneously with this part of the process, by the combustion of charcoal in the furnace D, carbonic-acid gas is generated,which,by means of the pipe E,is admitted at once into the chamber A, and by means of its superior specific gravity is diffused throughoi-itthe room or chamber. The carbonic acid thus introduced decomposes the subacetate of lead, and thus is formed the carbonate of the protoxide or white lead. This manipulation is continued, I without interruption until the metallic lead has undergone the desired change: T'heprm duct is then removed from the cnamtei-g-a new supply introduced, and the same'pro c'e'ss repeated.

I am aware that the vapor of water, acetic acid vapors, and carbonic acid have been used in Various ways in the manufacture of white lead. I therefore do not claim their use; broadly; but What I do claim as my improvement, and desire to secure by Letters Patent, is"

Subj'e'cting metallic lead placed'in a room or chambermade and kepttig'ht throughoutthe process, as specified, to the actionofa'queg ous and acetic-acid vapors conjointlyarid" continuously with c'arbo'nicacid gas until the process is completed, in the manner-substantially as and for t hepurpo'se set forth.

V GEO: CARY. Witnesses:

W. H. BURRI'DGE, HENRY VoTH. 

